YES We show the termination of the TRS R: div(X,e()) -> i(X) i(div(X,Y)) -> div(Y,X) div(div(X,Y),Z) -> div(Y,div(i(X),Z)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: div#(X,e()) -> i#(X) p2: i#(div(X,Y)) -> div#(Y,X) p3: div#(div(X,Y),Z) -> div#(Y,div(i(X),Z)) p4: div#(div(X,Y),Z) -> div#(i(X),Z) p5: div#(div(X,Y),Z) -> i#(X) and R consists of: r1: div(X,e()) -> i(X) r2: i(div(X,Y)) -> div(Y,X) r3: div(div(X,Y),Z) -> div(Y,div(i(X),Z)) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4, p5} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: div#(X,e()) -> i#(X) p2: i#(div(X,Y)) -> div#(Y,X) p3: div#(div(X,Y),Z) -> i#(X) p4: div#(div(X,Y),Z) -> div#(i(X),Z) p5: div#(div(X,Y),Z) -> div#(Y,div(i(X),Z)) and R consists of: r1: div(X,e()) -> i(X) r2: i(div(X,Y)) -> div(Y,X) r3: div(div(X,Y),Z) -> div(Y,div(i(X),Z)) The set of usable rules consists of r1, r2, r3 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: div#_A(x1,x2) = ((0,0),(1,0)) x1 + ((0,0),(1,0)) x2 + (3,2) e_A() = (2,2) i#_A(x1) = ((0,0),(1,0)) x1 + (3,3) div_A(x1,x2) = ((1,0),(1,1)) x1 + x2 + (2,5) i_A(x1) = ((1,0),(1,1)) x1 + (0,1) precedence: i# > div# = e = div = i partial status: pi(div#) = [] pi(e) = [] pi(i#) = [] pi(div) = [1] pi(i) = [1] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: div#_A(x1,x2) = (2,1) e_A() = (1,0) i#_A(x1) = (0,0) div_A(x1,x2) = (2,0) i_A(x1) = (2,0) precedence: div# = div = i > e = i# partial status: pi(div#) = [] pi(e) = [] pi(i#) = [] pi(div) = [] pi(i) = [] The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: div#(X,e()) -> i#(X) p2: div#(div(X,Y),Z) -> i#(X) p3: div#(div(X,Y),Z) -> div#(i(X),Z) p4: div#(div(X,Y),Z) -> div#(Y,div(i(X),Z)) and R consists of: r1: div(X,e()) -> i(X) r2: i(div(X,Y)) -> div(Y,X) r3: div(div(X,Y),Z) -> div(Y,div(i(X),Z)) The estimated dependency graph contains the following SCCs: {p3, p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: div#(div(X,Y),Z) -> div#(i(X),Z) p2: div#(div(X,Y),Z) -> div#(Y,div(i(X),Z)) and R consists of: r1: div(X,e()) -> i(X) r2: i(div(X,Y)) -> div(Y,X) r3: div(div(X,Y),Z) -> div(Y,div(i(X),Z)) The set of usable rules consists of r1, r2, r3 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: div#_A(x1,x2) = ((1,0),(1,1)) x1 + (1,2) div_A(x1,x2) = ((1,0),(1,1)) x1 + x2 + (2,1) i_A(x1) = ((1,0),(1,1)) x1 e_A() = (1,0) precedence: i > div# = div > e partial status: pi(div#) = [1] pi(div) = [2] pi(i) = [] pi(e) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: div#_A(x1,x2) = x1 + (1,1) div_A(x1,x2) = x2 + (2,2) i_A(x1) = (0,0) e_A() = (0,1) precedence: i > div > div# > e partial status: pi(div#) = [1] pi(div) = [] pi(i) = [] pi(e) = [] The next rules are strictly ordered: p1 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: div#(div(X,Y),Z) -> div#(Y,div(i(X),Z)) and R consists of: r1: div(X,e()) -> i(X) r2: i(div(X,Y)) -> div(Y,X) r3: div(div(X,Y),Z) -> div(Y,div(i(X),Z)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: div#(div(X,Y),Z) -> div#(Y,div(i(X),Z)) and R consists of: r1: div(X,e()) -> i(X) r2: i(div(X,Y)) -> div(Y,X) r3: div(div(X,Y),Z) -> div(Y,div(i(X),Z)) The set of usable rules consists of r1, r2, r3 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: div#_A(x1,x2) = ((1,0),(1,1)) x1 + x2 + (1,1) div_A(x1,x2) = ((1,0),(1,1)) x1 + x2 + (3,3) i_A(x1) = ((1,0),(1,1)) x1 + (0,2) e_A() = (1,1) precedence: div# = div = i = e partial status: pi(div#) = [] pi(div) = [] pi(i) = [] pi(e) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: div#_A(x1,x2) = ((1,0),(1,1)) x1 + ((1,0),(1,1)) x2 + (1,1) div_A(x1,x2) = ((1,0),(1,1)) x1 + ((1,0),(1,1)) x2 + (3,1) i_A(x1) = x1 + (2,3) e_A() = (1,2) precedence: div# = div = i = e partial status: pi(div#) = [] pi(div) = [] pi(i) = [1] pi(e) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.